Pneumatic door closers have been known for many years. Generally, a pneumatic door closer is used to permit a door to be opened and then to gradually shut without slamming. Often it is desired for a door to be held open, permitting a person to come in and out more easily. This has often been done with a washer placed on a rod that is manually moved or slid along the rod to a position adjacent a pneumatic cylinder for locking on a rod and holding the door open. This often requires the use of two hands, one for holding the door open and the other for moving or sliding the washer to a position adjacent the pneumatic cylinder of the door closer. Also, to close the door, two hands are often needed; one for holding the door open and the other for moving or sliding the washer away from the pneumatic cylinder and into a home position permitting the door to close. This has proven to be very inconvenient because often a person is carrying something in one hand and does not have the two hands required for holding the door in an open position. Efforts have been made to develop a different more convenient door closer that is easier to hold open and close without the need for two free hands.
One such device that has worked well and has achieved wide-spread acceptance is a door closer disclosed in U.S. Pat. No. 5,832,562 issued to Luca on Nov. 10, 1998 and entitled “Door Closer”, which is herein incorporated by reference. Therein disclosed, in one embodiment, is an arming or latching mechanism having an internal coiled spring and a trigger used to automatically hold a door open. While the arming or latching mechanism disclosed therein has worked well, it is comprised of multiple parts that require manufacture and assembly and therefore has a higher cost.
Accordingly, there is a need to continuously improve door closers, and particularly for providing a hold-open mechanism that is less expensive to manufacture.